Neuromuscular Junction

Q.

What is physiological function

Q.

Which of the following can be termed as opposite of Bohr's effect ?

1. Hering-breuer reflex

2. Hamburger's effect

3. Haldane's effect

4. None of these

Q.

Do muscles relax when insufficient ATP is available?

Q. Axon of a neuron and muscle fibres it innervates together form

1. Motor unit
2. Sensory unit
3. Axon unit
4. None of these

Q.

How is calcium used in cell division?

Q.

Which of the following is not correct?

1. Acetylcholine is the Neurotransmitter

2. Acetylcholine binds to the receptor channels at the motor end of the plate of the muscles

3. The calcium causes the release of acetylcholine

4. Neuromuscular junction is between the motor nerve and skeletal muscle.

Q.

Read the following statements about muscle contraction in humans:

i. Chemical energy is converted into mechanical energy during muscle contraction

ii. Acetylcholineeasterase is an enzyme that catalyzes the production of acetylcholine

iii. In a contracted muscle, volume remains the same.

iv. A contracted muscle becomes shorter and thicker.

1. only iv) is correct.

2. only i) and iv) are correct.

3. only ii), iii) and iv) are correct.

4. only i), iii) and iv) are correct.

Q.

Stimulation of a muscle fiber by a motor neuron occurs at

1. The neuromuscular junction

2. The transverse tubules

3. The myofibril

4. The sarcoplasmic reticulum

Q. Which one of the following is a product of both cyclic and noncyclic photophosphorylation ?

1. NADPH
2. ATP
3. PSI and PSII both
4. $O_2$

Q. Which one of the following is a product of both cyclic and noncyclic photophosphorylation ?

1. ATP
2. $O_2$
3. PSI and PSII both
4. NADPH

Q. During muscle contraction, which of the following decreases in size?

1. I band
2. A band
3. H zone
4. Both A and C

Q.

Read the following statements about muscle contraction in humans:

i. Chemical energy is converted into mechanical energy during muscle contraction

ii. Acetylcholineeasterase is an enzyme that catalyzes the production of acetylcholine

iii. In a contracted muscle, volume remains the same.

iv. A contracted muscle becomes shorter and thicker.

1. Only iv) is correct.

2. Only i) and iv) are correct.

3. Only ii), iii) and iv) are correct.

4. Only i), iii) and iv) are correct.

Q. Which statements about muscle contractions are true?
(i) Acetylcholine is released when neural signal reaches motor end plate
(ii) Muscle contraction is initiated by a signal sent by CNS via a sensory neuron
(iii) During muscle contraction, isotropic band gets elongated
(iv) Repeated activation of the muscle can lead to lactic acid accumulation.

1. i and iv
2. i and iii
3. ii and iii
4. i, ii and iii
5. i and ii

Q. Longest nerve in human body is

1. sciatic nerve
2. radial nerve
3. median nerve
4. ulnar nerve

Q.

During an action potential, what is the role of calcium?

1. The calcium binds to the myosin molecule in the sarcomere.

2. The calcium causes the release of acetylcholine in the neuron into the synaptic cleft.

3. There is no role for calcium during action potential.

4. The calcium breaks down ATP to ADP and inorganic phosphate.

Q. Write down the biochemical events in the mechanism of muscle contraction?

Q. Assertion :Upon stimulation of a muscle cell, calcium ions $\left(C{a}^{++}\right)$ are released from the sarcoplasmic reticulum. Reason: In recating with a protein complex, $C{a}^{++}$ uncover active sites on the actin filaments.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. what are the functions of basal body , hook and filament

Q. Which of these ions are involved in muscle contraction?

1. $C{a}^{2+}$ and $M{g}^{2+}$
2. $C{a}^{2+}$ and $N{a}^{+}$
3. $N{a}^{+}$ and $K^{+}$
4. $M{g}^{2+}$ and $K^{+}$

Q.

The Junction between a nerve cell and the motor unit is called

1. Gap junction
2. Tight junction

3. Neuromuscular junction

4. Sarcomeres

Q.

Given below is a randomly arranged list of events that occur at the neuromuscular junction to trigger muscle contraction.Which of the following gives the correct sequence of these steps?

(i) Acetylcholine binds to the receptor sites on sarcolemma

(ii) Nerve impulse

(iii) Release of Ca+2 from sarcoplasmic reticulum

(iv) The neurotransmitter acetylcholine is released

(v) Sarcomere shortens

(vi) Acetylcholine diffuses across the synaptic cleft

(vii) Spread of impulses over sarcolemma on T-tubules

1. (ii), (iv), (i), (vi), (vii), (iii), (v)

2. (ii), (iv), (vi), (i), (vii), (iii), (v)

3. (i), (ii), (iii), (iv), (v), (vi), (vii)

4. (vii), (vi), (v), (iv), (iii), (ii), (i)

Q. Following muscle contraction in response to a stimulus, the muscle temporarily cannot respond. This is known as:

1. Motor end plate
2. Refractory period
3. Summation period
4. Oxygen debt

Q. How does calcium affect the process of muscle contraction?

Q. Nerve impulses are initiated by nerve fibres only when the membrane shall become more permeable to

1. Adrenaline
2. Phosphorus
3. Sodium ions
4. Potassium ions

Q. Which of the following is not involved in muscular contraction?

1. Calcium ion
2. Troponin
3. Actin
4. Magnesium ion

Q. Mark the option which is not a component of $I-band$ in a skeletal muscle fibre?

1. Actin
2. Troponin
3. Meromyosin
4. Tropomyosin

Q. Which among the following is not involved in the muscular contraction?

1. Mg ion
2. Actin
3. Troponin
4. Ca ion

Q. ATP-ase needed for muscle contraction is present over

1. Aetinin
2. Troponin
3. Myosin
4. Actin

Q. Give an account on the length of sarcomere during muscle contraction.

Q. Short/ Long answer type questions.
As a result of an automobile accident, 50 per cent of the muscle fibres in the biceps muscle of a person were destroyed. Ten months late; the biceps muscle was able to generate 80 per cent of its original force. Describe the changes that took place in the damaged muscle that enabled it to recover.